Tensioning and detent means for strip film projectors



Dec. 23, 1952 T. l. REss 2,522,476

TENSIONING AND DETENT MEANS FOR STRIP FILM FROJECTORS Filed Sept. 28,1946 6 Sheets-She??l l Dec. 23, 1952 T. l. REss 2,622,476

TENSIONING AND DETENT MEANS FOR STRIP FILM PROJECTORS Filed Sept. 28,1946 6 Sheets-Sheet 2 Dec. 23, 1952 T. l. REss 2,622,476

TENSIONING AND DETENT MEANS FOR STRIP FILM PRoJEcToRs Filed Sept. 28,1946 6 Sheets-Sheet 3 Dec. 23, 1952 1'. l. Rr-:ss 2,522,475

TENsoNING AND DETENT MEANS FOR STRIP HLM PRoJEcToRs Filed Sept. 28, 19466 Sheets-Sheet 4 Dec. 23, 1952 T. l. REss 2,622,476

TENsIoNING AND DETENT MEANS FOR STRIP FILM PRoJEcToRs Filed Sept. 28,1946 6 Sheets-Sheet 5 Dec. 23, 1952 'r. l. REss 2,622,476

TENsIoNING AND DETENT MEANS FOR STRIP FILM PRoJEcToRs Filed sept. 28,i946 e sheets-sheet e Patented Dec. 23, 1952 TENSIONING AND DETENT MEANSFOR STRIP FILM PROJECTOR/S Thomas I. Ress, Chicago, Ill., as signor, byniesne assignments, to Ampro Corporation, Chicago, Ill., a corporationof Illinois Application September 28, 12946, Serial No. '700,087

(C1. sra-28) 17 Claims.

second sprocket at the other end of the film guide for normally feedingthe lm to the film guide, wherein a detent mechanism is provided for thefirst sprocket for moving the film predetermined amounts, wherein afriction brake is provided for the second sprocket to hold back andprovide tension to the lm on the lm guide, wherein means are providedfor positioning the first sprocket with respect to the action of thedetent mechanism, wherein a resilient lost motion driving `connection isprovided between the friction brake and the second sprocket, wherein thesecond sprocket provides for reverse feed of the film, wherein pivotedarms controlled by pivoted levers are provided for holding the filmagainst the sprockets, wherein a container open on the side is providedfor supporting the rolled nlm, and wherein one of the pivoted leversretains the rolled lm in the container.

Further objects of this invention reside in the details of constructionof and the cooperative relation between the component parts utilized inproviding the above-mentioned features of the invention.

Other objects and advantages will become apparent to those skilled inthe art upon reference to the accompanying specification, claims, anddrawings, in which- Figure 1 is a side elevational view of theprojection machine;

Figure 2 is a vertical sectional view through the projection machine ofFigure 1;

Figure 3 is a side elevational View of the light concentrating box;

Figure 4 is a front elevational View of Figure 3 Figure 5 is a sectionalview taken substantially along the line 5-5 of Figure 3;

Figure 6 is a perspective view of one of the plates for supporting thefilters and concentrating lenses;

Figure '7 is a front elevational view of the projection machine with theslide shifter in place;

Figure 8 is a perspective view of a shield for covering the sideopenings of the slide shifter support;

Figure 9 is a partial side elevational View similar to Figure 1, butillustrating the slide shifter in place;

Figure 10 is a vertical front sectional view taken substantially alongthe line Ill-I0 of Figure 1;

Figure 11 is a partial perspective view of a part of the mechanism shownin the upper portion of Figure 10;

Figure 12 is a partial perspective view showing a part of the mechanismof the lower portion of Figure 10;

Figure 13 is a elevational view of the lower knob of Figure 10 lookingfrom the right;

Figure 14 is an enlarged partial sectional view of the film guidingmechanism showing the pivoted arms in free position;

Figure 15 is a view similar to Figure 14, but showing the pivoted armsin guiding position;

Figure 16 is a partial perspective view of a portion of the container ofFigure 14;

Figure 17 is a perspective View of the lower pivoted lever of Figure 14.

The projection machine is generally designated at IB in Figures 1, 2,and 7 and it includes a base II provided with supporting feet I2. Thebase i I is also provided with internal pins I3 received in openings inthe side walls of a lamp box I4. The lamp box I4 is substantiallyrectangular in cross section and is open at the top and bottom, as shownin Figure 2. Across the bottom of the lamp box is suitably secured astrip I5 for carrying a lamp vsocket I6 which in turn receives a lamplI'I having an opaque top I8. Electrical energy is supplied to the lampsocket IB and hence to the lamp I'I by a cord I9 provided with alsuitable plug 20. lA switch 2I makes and breaks the electricalconnections for turning on and off the lamp I1.

A wheel 23 carried bya screw threaded shaft 24 is provided with abearing extension 25 rotating in a bearing sleeve 26 carried by the baseII. The screw threaded shaft 24 extends upwardly through an opening 21in the strip I5 and the screw threadedly engages a nut 28 carried by aleaf spring 29 which in turn is secured to the lamp box I4 by a screw30. By rotating the wheel 23 in one direction, the nut 28 is drawndownwardly to cause clockwise'movement of the lamp box I4 about thepivots I3, thereby tilting the projection machine in one direction. Uponreverse rotation of the wheel 23, ,the nut 28 is driven upwardly wherebythe lamp box I4 is moved in a counter-clockwise `direction about thepivots I3 to tilt the projection machine in the `opposite direction.Alignment of the projection machine is thus provided.

The lamp box I4 is internally provided in the back thereof with a sheet32 of insulating material to protect the box from the heat given off bythe lamp I1. Suitably secured, as by welding, to the upper end of thelamp box I4 is a flange 33 which receives `a latticed cover 34. Thecover 34 is open, but is provided with a criss-cross lattice formed fromstrips 35. Some of the lattice strips, such as 36, extend downwardly andare secured, as by welding, to a light-concentrating box 31 forsupporting the latter. The light-concentrating box 31 encompasses thelamp I1 and is provided on its sides, as shown in Figures 3 to 5, withspring arms 38 having catches 39 adapted to be received under the flange33 for holding the cover 34 and light-concentrating box 31 in the lampbox I4. The ends of the spring arms 38 are provided with buttons 40extending through suitable openings in the cover 34 whereby the springarms 38 may be pressed inwardly to release the catches 39 from under theflange 33 so that the cover 34 and the light-concentrating box 31 may beremoved.

The rear of the light-concentrating box 31 is provided with an opening42 for receiving a concave reflecting mirror 43 which is carried byclamps 44 in turn secured by a rivet 45 to a bracket 46. The bracket 46is secured by screws 41 to the light-concentrating box 31 for holdingthe reflector 43 in the opening 42.

The light-concentrating box 31 is provided internally with a pair ofconcentric cylinders 50 and I, the cylinder 50 being suitably secured tothe cylinder 5| and the latter being secured bybrackets 52 to the sidewalls of the light-concentrating box 31. The inner cylinder 50terminates short of the reflector 43 and the outer cylinder 5| isprovided with openings 53 and 54 to permit the light generated by thelamp I1 to be reflected forwardly by the reflector 43. The opaque top I8of the lamp I1, when taken in conjunction with the cylinders 50 and 5Iand the latticed cover 34, prevents light from escaping from the lightbox I4, while at the same time, providing free circulation of airthrough the lamp box I4 to dissipate the heat generated by the lamp I1.

Secured, as by welding, to the front of the light concentrating box 31are U-shaped brackets 56 and 51 which provide supports for the filtersand concentrating lenses. The bracket 51 is provided with a plurality ofnotches 58 of the same depth, and the bracket 56 is provided with aseries of notches 59, 60, 6|, and 62 of varying depth. The bracket 51rand the front wall of the light-concentrating box 31 are provided withaligned holes 63.

The Various notches are adapted to receive plates 65, 66, 81, and 68respectively. The plates are of varying height and, therefore, cooperatewith the notches of varying depth to insure that plates `65, 66, 61, and68 may be received only in notches 59, 60, 6|, and 62 respectively. Theplates are provided with side flanges 69 to limit inward movement of theplates when they are inserted in the notches, the flanges engaging theside of the brackets 56 and 51. The plates are apertured and areprovided with fingers for securing the filters and the concentratinglenses in the plate apertures. Each of the plates is also provided witha hole 1|. As shown, the plates 65, 66, 61, and 68 carry respectively inthe apertures therein, a filter 12, a concentrating lens 13, a filter14, and a concentrating lens 15. A pin 16 is adapted to be insertedthrough the aligned holes 63 and 1| when the plates are properlyreceived in the notches. The pin 16, therefore, re-

tains the plates in position in the notches and the pin may be providedwith a hook 11 engaging the bottom bracket `51 for maintaining the pin"s6 in place.

By reason of this filter and concentrating lens supporting arrangement.the filter and concentrating lenses may be readily removed and cleanedand may be readily repositioned in the projection machine. The filterand concentrating lenses may only be positioned, in the projectionmachine in a predetermined sequence Whereby improper insertion thereofis prevented.

Referring now to Figures 2 and '1, the front of the lamp box I4 isprovided with an opening 30 `in alignment with the reflector 43 and thefilters and concentrating lenses, and secured to the front of the lampbox I4 is a frame split vertically in two parts 3| and 82. The frame isalso provided with an extension 83 for telescopingly receiving 'a tube84 carrying the focusing lens 85. A friction roller 86 operated by aknob 81 is utilized for longitudinally adjusting the tube 84 in theetxension 83 for focusing the projection machine.

The frame, composed of parts 8| and 82, is provided with a horizontalopening, the surfaces 90 surrounding which serve as a slide shiftersupport. This support is adapted to receive a slide shifter 9| carryinga shifting mechanism 92 operated by knobs 93. Slides may be inserted inthe shifting mechanism 92, and by manipulating the knobs 93, theslidesmay be brought into alignment with the opening in the lamp box I4.When the slide shifter 9| is removed from the slide shifter support 90,the side openings of the support 98 may be closed by a closure member94, as illustrated in Figure 8. One side of the closure member 94 isenlarged, as at 95, to limit the movement thereof `in the supmrt 90, andthe closure member 94 may be inserted or withdrawn by a knob 96. Thepurpose of the clesure member 94 is to prevent the passage of lightthrough the side openings in the slide shifter support 90. The slideshifter 9| or the closure member 94 may be retained in the slide shiftersupport 90 by means of a screw 91. The slide shifter 9| and the slidesoperated thereby are contained in one transverse plane between thesource of light provided by the lamp I1 and Ithe adjustable focusinglens 85.

A film guide 98, provided With a light transmitting aperture 99, is alsocarried by the frame 8|. The front face of the film guide 98, having theaperture 99, is preferably curved, as illustrated in Figures 2, 14, and15, so that When the film to be projected is drawn thereover, it isprevented from curling due to the heat from the lamp I1. The film guide98 is provided with lateral flanges, and one of these flanges carries lapair of pins |00 received in sleeves |0| carried between the frame parts0| and 82, as shown in Figure 10. The other flange of the film guide 98is provided with holes |02 for receiving the sleeves IOI. The pins |00and the holes |02, therefore, support the film guide 98 and permitlateral movement thereof out of the path` of light between theconcentrating lenses and the focusing lens. The film guide may belaterally moved by a suitable knob |03 carried thereby. In this way, thefilm guide with its relatively small aperture 99 may be moved out of thew-ay when slides are being projected.

The film guide 98 is in a different transverse plane between the sourceof light and the focusing lens than the slide support 90. and

ateatro the. location of the :slidesand thef,=f llm.; these differenttransverseplanes. Amay be -readilycom-'- pensated for-by properadjustmenttof thefocuszing lensf85-throug-h rota-tion lof the 'knoby83|.

When .it isV desired to proj-ect from film, the vfilmguide A38l with itsvaperture 99'is placed; inv the pathsof light, theslide shifter 9| .isremovedpasnd .the .'slide- .shifter support 9.0 is. closed by theclosuremember 94-as is illustrated .in Figures .41., l2, `and 110. When,however,y it Vis desired toUproj/ect Yfrom slides, the closure member 94is removed, the-slide shifter .9| is inserted in they slidemshifter'support 9.0, and the film guide -98 isi ymoved .out .of the path oflight, .as is. villustrated .in Figures 7 andai). This two-planeprojection arrangement .-'forvlm's and :slides therefore. .provides asimple means. for alternately .projecting -lm's or slides withoutthenecessityf'of `disrnantling the .projection- -machine and rconvertingitv from a slide projector to a 4film projector or vice versa.

The .film to` be.- projected .is drawn `across the -iilm lguide `98 by asprocket |505 'having teeth engaging in the usual `film` openings. Asfseen in Figure 1-0, the sprocket|05 is carried .by a shaft |01having akey -slot |08. rA pin |09 in the sprocket engages in the key slot'. |018Vsothat the sprocket |05 rotates with. the shaft |01.. One lend of theshaft |01 is journaled in a .boss IIB -on the frame part 82 v.and the.other `end of the shaft extends through a sleeve` I.|I mountedv in aboss I|.2 on the frame part: 8|. The sleeve .is provided with a shoulder||3 on one side of the boss |-I2 and Vcarries on the other side of theboss a friction washer I4 and a first .part ||5 of a detent mechanism.This .part I5 is provided with cam surfaces ||6 and an extension II1. Aspring Washer |.I8 abuts the detent part ||5 and lis held in place atthe rpeened-.over portion |9 of .the sleeve The .spring washer ||8 holdsvthe first part ||5 of the detent mechanism in engagement with thefriction washer |.|4. so that the detent .part I I5 is normallymain-tained Vstationary with respect to the frame 8|.

The detent mechanism includes -a `second part |2| carried on the shaft|81, and this second :part 1|2I is provided with a .pair of studs |22carrying cam followers or rollers |23. The rollers |23 engage the camsurfaces I6 of the iirst part .I |-5 of the detent mechanism.

The end of the shaft |-.01 is squared, as indicated .at |25, and .thissquared portion carries a knob |26 having .a squared opening 2.1engaging the end .of the shaft. .A screw |28 threaded into the .end ofthe shaft |21 holds the knob |26 on the shaft. A washer |29 also havinga squared .opening is .carried adjacent the end of the shaft and abutsthe inner surface of the knob |26. -A .spring |30 is .interposed betweenthe spring washer '|29 and the second .part |.2I of the detentmechanism. The spring performs a double 'function of urging the rollers|23 into engagement with the cam surfaces H5 and .urging the knob vI2|outwardly. The knob |26 is provided with an internal sleeve |3| providedwith four grooves |32. Two of the grooves |32 receive the studs |22.

VThe rollers |23 rest in the valleys between the :cam V'surfaces |16,whereby .normally holding the shaft |01 andthe sprocket |05 stationaryand .in ypredetermined positions. When the knob A|26 is rotated, i-t.rotates .the shaft |01 and hence the sprocket |05 .and it also rotatesthe second part I2| of the detent mechanism carrying the rollers |23therewith. The -rollers ride up the cam sur'- .faces |16 from one valleyand -then fall finto the .next valley'. .Thesprfineg 4:30 permits. therel-,1ers

|23 to befi'etracted; by the cam. surfaces, II'16 as -the shaft |01andthe sprocket |05- are moved .from one predetermined position to thenext. vIn this way, a detent mechanism is provided for movingl thesprocket |05 to .predetermined positionswith respect tothe .frame 8|.The partsare so arranged that the movement vof the mechanism from onedetent position to the next cor- .responds to the movement -of aAsing-le frame on the lm to be projected. Thus the detent mechanismcontrollingthe movement of the sprocket V|05 advances the film to .beprojected one frame at a time.

In order to line-.up the frame of .the film vto be projected vwith :the.aperture 98 in the film guide .98, .the .knob v|26 is `pressed inwardlyagainst the action of the spring-|30 and one of the 'grooves |32inthesleeve 5|3| formed in the knob .|26 enga-ges the extension II1 ofthe first part H5 of the detent mechanism. Upon rotation of the knob,lthe part .|-|5 is carried along.l so that the part I5 is .reset to the,proper vposition .inorder to line vup the lm with the aperture 99.

The lm to be projected is fed to the film guide 598 and .is .maintainedunder tension along the film guide 98 bya .hold back and reverse feedsprocket |35 having teeth |36 -engaging in the usual openings in thenlm. One end. of the sprocket |35 is secured to a stub shaft |31journaled in a boss |38 on the .frame part -82. The inner end of thestub: shaft |31 is provided with a slot |39. The other end of thesprocket |35 is rotatably mounted on a shaft |40 journaled 'in a boss|`4| formed onthe frame part 8|. The shaft .|40 is provided with aflange .|42 which .engages fa friction washer .|43 carried in the boss.|4I. A spring washer .|44 .is interposed between the .frame part -8Ianda :knob |45 which is vsecurely fastened to the shaft l| 40. Thespring washer |44 .urges the flange .|42 against the friction washer |43to provide a friction .brake for retarding the rotation of the shaft|40. The inner end of the -shaft .|40 is provided with a vslot |46. Atorsion spring |41 is carried in .the sprocket I|35 .and has its endsengaging in the slots |39. and |46. The flange |42 is provided with aflat-tened .surface |48 over which extends .a lpin |49 carried in theend of the sprocket |35. The attened surface |48 provides a pair ofspaced stops for the .pin |49 whereby a lost motion connection isprovided between the sprocket and Vthe shaft |40.

The torsion .spring |41 biases the sprocket |35 and :pin |49 .to therear, as viewed in Figures l0 and 1l., so that when the lm is drawn overthe film guide, the sprocket |35 is rst turned against the tension ofthe spring |41 'and then the pin |49 is brought into engagement with theforward edge of the flattened surface |48, at which time the shaft `|f40is 'caused to rotate Aagainst the action of `the friction brake. Thespring |41, therefore, holds back and maintains the lrn on the nlm guidein tension at all times, 'and as the `film is advanced, the shaft I-40is turned against the action of the friction brake. This placing oftension in the film while it is on the curved film guide preventscurling of the film due to the heat from the lamp |1. By manipulatingthe knob |45, the sprocket |35 may feed the nlm in the oppositedirection along the film guide thereby providing a reverse feed. Thedetent mechanism associated with the sprocket |05 will maintain the filmframes 'in 7 alignment with the aperture 99 in the film guide 98 duringthe reverse feeding of the film.

Located above the sprocket |35 is a container |55 for holding rolledfilm to be projected. The container is provided with a peripheral Wall|56 and is closed on one side, but open on the other. The open sidepermits lateral placement of the rolled film in the container |55. Apost |51 carried in the container may be utilized for carrying therolled film. The container |55 is secured to the frame by means ofscrews |58.

A pivoted arm |60 is utilized for holding the film against the sprocket|38. The pivoted arm |60 is provided with ears |6| pivoted to a shaft|62 which, in turn, is carried in the frame. A torsion spring |63 urgesthe pivoted arm |60 away vfrom the sprocket |35, as is shown in Figure14. The pivoted arm |60 is provided with slots |64 for accommodating theteethf|36 of the sprocket |35 and is also provided witha stop |65.

A pivoted lever |61 having a knob |68 is utilized for moving the pivotedarm |60 toward the sprocket |35 against the action of the torsion spring|63. In this connection, the pivoted lever |61 is provided with a crankarm portion |69 and is pivotallyr mounted in a bearing |10 carried bythe container |55.

When the pivoted lever |61 is in the position shown in Figure 14, thepivoted arm |60 is retracted by the spring |61 so that the film may beinserted in the container |55 and on the sprocket |35. After the film isin place, the lever |61 is moved from the position shown in Figure 14 tothe position shown in Figure where the portion |69 thereof engages thestop |65 and wherein the lever |61 is received in a catch |1| formed onthe container |55.' The lever |61 causes the pivoted arm to hold thefilm against the sprocket |35 and also extends across the open side ofthe container |55 to prevent the rolled film from falling out of thecontainer.

Located adjacent the sprocket |05 is a second pivoted arm |13 forholding the film against the sprocket 05. The pivoted arm |13 isprovided with ears |14 pivoted on a shaft |15 carried by the frame. Atorsion spring |16 biases the pivoted arm |13 away from the sprocket|05. The pivoted arm 13 is provided with slots |11 for accommodating theteeth |06 of the sprocket |05 and is also provided with a stop |10. Apivoted lever |19 having a knob |80 and a vcrank portion IBI is carriedby a bearing |02v carried on a guide |83 having a peripheral guideportion |84. The guide |83 is secured to the, frame by screws |35. Theperipheral guide portion |84 guides the film as it leaves the sprocket|05.

With the pivoted lever |19 in the position shown in Figure 14, thepivoted arm |13 is retracted by spring |16 so that the film may beplaced over the sprocket |05. When the pivoted lever |19 is moved to theposition shown in Figure 15, the pivoted arm |13 is moved toward thesprocket |05 against the action of the spring |16 to hold the film onthe sprocket |05. As will be noted in Figure 15, the pivoted lever |19is substantially normal to the pivoted arm |13 so that lthe spring |16has no tendency to swing the pivoted lever |19 from the position shownin Figure 15. In this way, the parts are locked in the Figure 15position. When, however, the lever |19 is moved out of the Figure 15position toward the figure position, the spring |16 urges and retainsthe parts in the position shown in Fig- 'ure 14.

The pivoted arms |60 and |13 and the pivoted levers |61 and |19 providea simple mechanism for maintaining the film against the sprockets |35and |05, but still permit ready insertion and removal of the film. Inaddition, the pivoted lever |61 provides the further function ofmaintaining the rolled film in the container |55.

Generally speaking, the claims of this application are directed to thedetent mechanism, to the friction brake and lost motion connection, tothe reverse feed arrangement, to the pivoted arms and associated pivotedlevers, and to the container for the rolled film and combinationsthereof. The disclosed features relating to the twoplane arrangement forprojecting slides or film, tothe friction brake and reverse feed, and tocombinations thereof, are claimed in the copending application of ArthurJ. Bradford, Serial No. 700,049, filed September 218, 1946, now PatentNo. 2,553,075, issued May l5, 1951.

While for purposes of illustration one form of this invention has beendisclosed, other forms thereof may become apparent to those skilled inthe artv upon reference to this disclosure,- and, therefore, thisinvention is to be limited only by the scope of the appended claims.

What is claimed is:

1. In a projection machine having a frame and a film guide for a film, asprocket for drawing the film along the lm guide, a shaft journalled inthe frame and carrying the sprocket for rotating the same, a detentmechanism having a first part mounted on the frame and a second partrotatable by the shaft, a friction device comprising contacting surfacesrespectively secured to the frame and the first part of the detentmechanism normally retaining the first part of the detent mechanismfixed with respect to the frame but permitting movement with respectthereto, a knob on the shaft for rotating 4the shaft and the second partof the detent mechanism predetermined amounts determined-by the detentmechanism, and means on the knob operated by longitudinal movement ofthe knob for engaging the first part of the detent mechanism to rotatesaid part against the action of the friction device.

2. In a projection machine having a frame and a nlm guide for a film, asprocket for drawing the iilm along the film guide, a shaft journalledin the frame and carrying the sprocket for rotating the same, a detentmechanism having a first part secured to the frame and provided with camsurfaces and a second part rotatable by the shaft and provided with camfollowers cooperative with said cam surfaces, a friction devicecomprising a friction surface fixed to the frame and a contactingfriction surface secured tothe first partof .the detent mechanismnormally retaining said part fixed with respect to the frame, a knobslidably mounted on the shaft for rotating the shaft, a springinterposed between the knob and the second part of the detent mechanismfor biasing said second part into engagement with the first part of thedetent mechanism, means on the knob engaging the second part of thedetent mechanism for rotating said second part with the shaft, and meanson the knob engaging the first part of the detent mechanism upon slidingof the knob against the action of the spring for rotating said firstpart against the action of the friction devi-ce.

3. In a projection machine having a frame and a film guide for a film, asprocket for guiding the film to the film guide arranged to be turned bylm as it is fed to said guide, a shaft the sprocket, a friction brakebetween the shaft and the frame, a lost motion driving-connectionbetweenl the shaft and the sprocket permitting limited lrelativemovement between them, and a spring between the shaft and the sprocketarranged to be tensed by turning, of the sprocket in the direction ofadvancing film feed and-relative to-'the shaft to onelimitof suchrelative rotativemovement for biasing the shaft to rotate relative tothe sprocket and in the direction/opposite to such relative movement.

4. In a projection machine having a frame a-nd a film guide for a film,a sprocket for guiding the film tol the film guide arranged to betur-ned byfilm as it is fed to said guide, a shaft journall'ed in theframe for rotatably'supporting the sprocket and provided with spacedstops, a frictionv bra-ke between` the shaft and the frame, a pincarried by the sprocket and extending between the spaced stops on theshaft to provide a lost motion vdriving connection between the sprocketand the shaft, and a spring between 'the shaft and the sprocket arrangedto be tensed byfturning of the sprocket byfilml approaching the filmguidefor biasing nthe pin against one of thestops.

5. Ina projection machine having a frame and a lmguide for a film, aVsprocket arranged for guidingthe film toit-lieV film guide' arranged tovbe turned by film as it isfed to saidv guide, a shaft journalled in theframe for rotatably supporting the sprocket, a-r friction brake betweenthe shaft and the frame, a lost motion driving connection between theshaft' and the sprocket permitting limitedrel'ative rotativeimove'm'entbetween-them, a slot in the shaft, a slot in the sprocket, and a torsionspringzextendingin said slots for biasing the lost motion drivingconnection in one direction.

6. Ina projection machine having a frameand a film guide for a film, asprocket for guiding the film to the film guide arranged.- to be turned.

by filmas it is fedv to said guide, a shaftjournailed in theframefoi-rotatably supporting the sprocketandprovided with spaced stops, afriction brake between the 'shaft andy the frame, a pin carried by thesprocket and' extending between the-'spaced stops on the shaft to'provide a lost motion, driving connection between the sprocket andl theshaft, a slot in the shaft, a slot in the sprocket, yandV a torsionspring extending in; said slots f'or biasing the pin against one of theslots.

7; Ina projection machine for 'a rolled film having-a sprocket forguiding the film, a container open on the side for supporting the rolledfilm, a pivoted arm for holding the film against the sprocket, and apivoted lever for engaging the pivoted arm for moving the arm toward thesprocket and extending across the open side of the container forretaining the rolled film therein.

8. In a projection machine for a rolled film having a sprocket forguiding the film, a container open on the side for supporting the rolledfilm, a pivoted arm for holding the film against the sprocket, springmeans for biasing the pivoted arm away from the sprocket, and a pivotedlever for engaging the pivoted arm for moving the arm toward thesprocket and extending across the open side of the container forretaining the rolled film therein.

9. In a projection machine for a rolled film having a sprocket forguiding the film, a container open on the side for supporting the rolledfilm, a pivoted arm for holding the film against 104 the sprocket,spring: means for biasing the pivoted arm away from the sprocket, apivoted lever for engaging the pivotedarm for movingV the arm toward thesprocket and` extendingacross the open side of the container forretaining the rolled filmI therein, and a catch onv the containerforreceiving and retaining the pivoted lever.

10. In a projection machine for a rolled film having a film guide, a,`first sprocket at one end of the film guide for drawing, the film alongthe film guide, a second sprocket at the other end of the film guide forfeeding the iilmto the film guide, a first pivoted arm for holding thefilm against the first sprocket, a first pivotedlever forengaging thefirst pivoted arm for moving the first arm toward the first sprocket, asecond pivoted arm for holding theA film against the second sprocket,and a second pivoted lever forengaging the second pivoted' arm formovingthe second pivoted arm toward the second sprocket.

1l. In a projection machine fora rolled film having a film guide, afirst `sprocket at one end of :thefilm guide for drawing the film alongthe film guide, a second sprocket at the other end of the film guide forfeeding thelm to the film guide, a first pivoted arm for holding thefilm against the first sprocket, `a first lever for engaging the firstpivoted arm for moving the first arm toward the first sprocket, acontainer open on the side for supporting therolled film', a secondpivoted arm for holding the film4 against the second sprocket, andasecondpivoted lever for engagingV the secondpivotedarm vfor moving thesecond pivoted arm toward the rsecond sprocketand extending. across theopen side of the container for retaining the .rolled film therein.

1.2. In .a projection machine for a rolled film having a iilm guide, afirst sprocket a-t one end of the film guidefor drawing the film alongthe gaging the second pivoted arm for moving ther second pivoted armtoward the secondtsprocket, a detent mechanism for the first sprocketfor moving the film a predetermined amount,.and a friction brake for thesecond sprocket for applyingtensionto the film on theifilm guide.

13. .In a projection machine for a rolled` film having a film guide, afirst sprocket at one end of the lm guide for drawing the film alongIthe film guide, a, second sprocket at the other end of the film guidefor feeding the film to the film guide, a first pivoted arm for holdingthe film against the first sprocket, a first lever for engaging thefirst pivoted arm for moving the first arm toward the first sprocket, acontainer open on the side for supporting the rolled film, a secondpivoted arm for holding the film against the second sprocket, and asecond pivoted lever for engaging the second pivoted arm for moving thesecond pivoted arm toward the second sprocket and extending across theopen side of the container for retaining the rolled film therein, adetent mechanism for the first sprocket for moving the film in apredetermined amount, and a friction brake for the second sprocket forapplying tension lto the film on the film guide.

14. In a projection machine for a, rolled film film guide, a secondsprocket at the other end of the nlm guide for guiding the film to thefilm guide, a first pivoted arm for holding the film against the firstsprocket, a rst pivoted lever for engaging the first pivoted arm formoving the first arm toward the rst sprocket, a second pivoted arm forholding the film against the second sprocket, a second pivoted lever forengaging the second pivoted arm for moving the second pivoted arm towardthe second sprocket, a detent mechanism for the first sprocket formoving the film a predetermined amount, and a friction brake fojr thesecond sprocket for applying tension to the lm on the film guide, meansfor positioning the nrst sprocket with respect to the action of thedetent mechanism, and a resilient connection between the friction brakeand the second sprocket.

15. In a projection machine for a rolled film having a sprocket forguiding the film, a plate curved to correspond to curvature ofthesprocket and an arm supporting said plate at one end and pivotallymounted at the other for swinging the plate to and from a position forholding film against the sprocket, spring means biasing the pvoted armand plate away from such position, and a lever pivotally mounted andarranged for engaging the side of the curved plate away from thesprocket for swinging the plate toward its film-holding position.

16. In a projection machine fora rolled film having a sprocket forguiding the film, a plate arcuately curved to correspond to curvature ofthe sprocket, an arm supporting said plate at one end and pivotallymounted at the other for swinging the plate to and from a positionwherein the plate is adjacent and substantially coaxial with thesprocket for holding lm against the sprocket, spring means biasing thepivoted arm and plate away from such position, and a lever pivotallymounted in arrangement for engaging the curved side of the plate awayfrom the sprocket, when the plate is away from its film-holdingposition, said lever being arranged for moving Vthe plate toward suchposition as the lever swings, and movable .to a dispositionsubstantially normal to the curve of such plate when in its film-holdingposition for maintaining the plate in such posil tion.

Y17. Ina projection machine for projecting still pictures from strip lmand that includes a film guide defined at one side by anaperture-forming film-guiding surface, and 'a sprocket mounted at theexit end of the guide for engaging film trained` through the guide andadvancing such film by rotation; means for advancing such lilm throughfthe guide in increments of preselected length and for maintaining filmin the guide under tension between advances of such increments, saidmea-ns comprising detent mechanism for indexing said sprocket in angularpositions spaced to :advance by sprocket rotation between them suchincrements of a lm engaged with said sprocket, a second sprocket spacedalong said guide from `the first said sprocket to the opposite side ofthe aperture formed by said surface for engagement with a film in theguide and to be rotated thereby during advance of such lm by the firstsaid sprocket. a rotatable element mounted adjacent said secondsprocket, friction brake means resisting rotation of said element, alost motion connection between said second sprocket and said rotatableelement arranged to permit limited relative rotation between them, andresilient means interconnecting said second sprocket and element andarranged to be tensed by rotation of the sprocket in the directioncorresponding to forward feed of film in the guide engaged therewith,said friction brake means having a characteristic of resistance torotation of said element greater than the characteristic of resistanceby tensing of said resilient means to advancing rotation of said secondsprocket relative to said element.

THOMAS I. RESS.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,057,234 Green Mar. 25, 19131,262,578 Cameron Apr. 9, 1918 1,513,920 Mechau Nov. 4, 1924 1,548,573Ackley Aug. 4, 1925 1,738,762 De Vault Dec. 10, 1929 1,805,579Goldhammer May 19, 1931 1,882,303 Seaholm Oct. 11, 1932 1,939,561 MartinDec. 12, 1933 2,073,224 Ross Mar. 9, 1937 2,076,853 McClure Apr. 13,1937 2,084,473 Becker June 22, 1937 2,092,064 Hanna et al Sept. 7, 19372,120,249 Holman June 14, 1938 2,126,474 Kleerup Aug. 9, 1938 2,231,743Young et al Feb. 11, 1941 2,251,077 Stanton July 29, 1941

